This disclosure relates to dynamic frequency selection (DFS) in wireless data radio systems to avoid interference and/or comply with technical specifications.
Wireless data radio systems must comply with various technical specifications depending on the jurisdiction in which the radios operate. Some of these technical specifications may require a wireless data radio system operating in certain frequency bands to support dynamic frequency selection (DFS) to avoid specific types of interference. For example, the ETSI EN 302 502 specification requires wireless data radios operating in the 5725 to 5850 MHz frequency band to use DFS to avoid radar interference. Similarly, the FCC Part 90 specification (specifically, the FCC Part 90.1319 specification) requires interference avoidance in the upper 25 MHz of the frequency band from 3.650 to 3.700 GHz, which may be accomplished using DFS. Some Part 90 wireless data radios, however, may avoid such interference by simply failing to operate in these frequency bands. Alternatively, some Part 90 wireless data radios may carry out a simplified form of interference avoidance by temporarily ceasing transmissions when any type of interference is detected. Doing so, however, may leave a high likelihood that the interference will continue to be present on that channel. In addition, many conventional wireless data radio modems and/or processors may attempt to detect interference such as radar interference, but frequently may falsely detect interference. This may reduce the ability of the wireless data radio system to maintain communication for long periods of time, even when interference, such as radar, is not present.